Egyptian authorities arrested at least 18 suspected radical Islamists following last week's mob attack on Christian homes and properties in the Sohag Governorate in Upper Egypt.

The attack injured at least four Christian Copts, destroyed a Christian-run guest house, burned down four Coptic-owned shops and badly damaged nine houses.

The attack was reportedly prompted by rumours that Christians were planning to build a new church in the village of Manshiet El-Naghamish, The Catholic Herald reported, citing the non-profit group International Christian Concern as its source.

The rumours turned out to be unfounded as what was being built in the community was just a four-story building to be used by residents as a community centre, nursery and retirement home, officials said.

The residents of the village were actually still securing a government permit to build an actual place of worship in the village, but have not been granted yet the necessary permits.

More than 2,000 Christians live in the village and the nearest church is more than three miles away. They reportedly wanted to build a church in their own village to make it easier for them to worship. It's not known whether they will still push through with their plan following the latest attack.

Samir Nashed, a Christian resident of El-Naghamish, said the attack appeared to be well organised as the attackers came to the village carrying weapons.

"Following the Muslim prayers, a great deal of fanatic Muslim young men [came]. Some of them were carrying gas canisters and rocks while others came armed with automatic rifles, clubs, machetes and knives. They attacked Copts and Coptic-owned houses," Mashed said.

He said the attackers appeared intent on causing maximum damage to the Christian neighbourhood since they "cut [off] the road so that the fire trucks could not enter the village" and that "they also cut off the water and power supply to the village."